A woman accused of fatally stabbing her boyfriend told police she would have grabbed a spoon if it had been there.

But the first thing Juliette Anne Gerbes grabbed was a large knife.

Christopher Jones, 22, died from the stab wounds to his stomach on October 13, 2012.

Gerbes, 21, was holding the knife when he was stabbed. But she says Jones grabbed the knife during an argument and pulled the blade into himself.

She is defending a manslaughter charge in the High Court in Napier.

The court heard Gerbes and Jones began fighting verbally and physically after they had been drinking at a party on October 12, 2012.

At home, Jones had tried to initiate sex but Gerbes said she wasn't in the mood.

The couple tussled before Gerbes picked up a knife from the bench.

"I picked it up to scare him, or catch him out on his act or to shut him up, I don't know," she said in a police interview played to the court.

If a spoon had been on the bench she would have grabbed that, she said.

She suggested to police she should have grabbed the bread board and hit Jones with that instead.

Jones had grabbed her hands and pulled the knife towards him, she said.

"One minute I was holding the knife - next minute it was in him," Gerbes said.

"I wasn't trying to hurt him, maybe I was trying to be threatening or maybe it was as a joke," she said in a police interview.

She then suggested that perhaps she had let go of the knife when Jones pulled it towards him.

Gerbes told police she and Jones loved each other, but their relationship was full of drama. They had both given each other a black eye during past fights, the court heard.

She got upset when she discovered he had joined a dating website and sent photos of himself to other women.

He got angry when she texted other men.

Gerbes admitted she had hit Jones during arguments but told police she would never go to the extreme of stabbing him.

Forensic pathologist Martin Sage told the court the knife perforated Jones' major artery which lead to torrential blood loss. The stab wound below his rib cage was 52 millimetres long, Sage said. The knife went 150mm into his body.Jones was unconscious when he got to Hawke's Bay Hospital. Hours of emergency surgery could not save him.